1. Field of the Invention
The present invention relates to an inkjet printing apparatus and a check pattern printing method, and particularly relates to a technique of improving the detection accuracy of a check pattern for checking the predetermined characteristics of a printing apparatus.
2. Description of the Related Art
As this type of technique, Japanese Patent Laid-Open No. 2007-313744 discloses reading a test pattern as a plurality of divided images whose alignment marks overlap one another and obtaining primary coordinate data indicating, for each divided image, a print pattern corresponding to a print element based on one alignment mark and the position of the other alignment mark. The primary coordinate data is combined based on the overlapping alignment marks for the images, thereby obtaining secondary coordinates indicating the positions of the print patterns in the whole test pattern. Accordingly, Japanese Patent Laid-Open No. 2007-313744 discloses a checking and analyzing method capable of determining, with high precision, the relative positions of the print patterns in the whole test pattern.
However, in the technique disclosed in Japanese Patent Laid-Open No. 2007-313744, it is impossible to determine the positions of print patterns with high precision in a case where it is impossible to detect well an individual print patterns, in the first place. For example, in a case where the resolution of a reading optical system is not sufficiently high, it is impossible to clearly and distinctly detect individual patterns corresponding to nozzles of a print head, and accordingly, it is impossible to detect the positions of the patterns with high precision.
This problem may be solved by providing a reading optical system having high Modulation Transfer Function (MTF) or high SN sensitivity. However, this reading optical system produces a problem of increased cost.